Effect of sulfide on growth physiology and gene expression of Desulfovibrio vulgaris Hildenborough

Abstract

Hydrogen sulfide, the metabolic end product of sulfate-reducing bacteria (SRB), is toxic to most life forms. This includes the SRB themselves. Although many of these are probably among the most sulfide resistant life forms, the presence of sulfide nevertheless presents a stress, which SRB must overcome. Although the response of SRB, especially the genus Desulfovibrio, to numerous stressors has been studied, their response to sulfide stress is unknown. We determined the effect of sulfide stress by comparing cells of Desulfovibrio vulgaris Hildenborough grown under conditions in which sulfide accumulated (high sulfide, 10 mM) with cells grown under conditions in which sulfide was removed by continuous gassing (low sulfide, 1 mM). High sulfide decreased the instantaneous growth rate constant and the final cell density of the culture by 52 and 33%, respectively, indicating a decreased bioenergetic fitness. Changes in gene expression caused by exposure to high sulfide were determined using full-genome D. vulgaris microarrays. The transcription of ribosomal protein-encoding genes was decreased, in agreement with the lower growth rate of D. vulgaris under high sulfide conditions. Interestingly, expression of the gene for DsrD, located downstream of the genes for dissimilatory sulfite reductase was also strongly down-regulated. In contrast, the expression of many genes involved in iron accumulation, stress response and proteolysis were increased. This indicates that high sulfide represents a significant stress condition, in which the bioavailability of metals like iron may be lowered. Overall this leads to a reduced growth rate and less efficient biomass production.

Cadmium removal at high concentration in aqueous medium: mediated by Desulfovibrio alaskensis

“…Following this idea, the high cadmium concentration in the medium provoked a stress condition that induced the bacterium to produce EPS to form a protective barrier. In the control cultures, production of EPS was observed during the stationary phase, where H 2 S reached its maximum production (*600 mg/L), H 2 S accumulation causes a toxic effect on the cells (Caffrey and Voordouw 2009), despite the sulfate-reducing nature of the bacterium.…”

Reduced Glutathione Mediates Resistance to H 2 S Toxicity in Oral Streptococci

“…It has been reported that H 2 S elicited microbicidal effects by inhibiting the activities of superoxide dismutase and catalase (10,27). In addition, high levels of sulfide impose survival stress on Desulfovibrio vulgaris by sequestering essential trace metals (28). In this report, we showed that exogenously added H 2 S, as well as H 2 S derived from F. nucleatum, inhibited the growth and biofilm formation of S. mitis and S. oralis but not of S. gordonii and S. sanguinis.…”

Genetic basis for nitrate resistance in Desulfovibrio strains

“…These anaerobes produce sulfide as the end product of sulfate respiration (Postgate, 1984). Sulfide is toxic to most organisms (Caffrey and Voordouw, 2010), and its production causes oil souring in the petroleum industry (Ligthelm et al, 1991; Sunde et al, 1993). Despite the undesirable features of this metabolic end product, SRB have been exploited in studies of heavy metal bioremediation (Jiang and Fan, 2008; Martins et al, 2009) because of the ability of sulfide to form insoluble complexes with heavy metals (Jalali and Baldwin, 2000).…”